Pier \Pier\, n. [OE. pere, OF. piere a stone, F. pierre, fr. L. petra, Gr. ?. Cf. {Petrify}.] 1. (Arch.) (a) Any detached mass of masonry, whether insulated or supporting one side of an arch or lintel, as of a bridge; the piece of wall between two openings. (b) Any additional or auxiliary mass of masonry used to stiffen a wall. See {Buttress}. [1913 Webster] 2. A projecting wharf or landing place. [1913 Webster] {Abutment pier}, the pier of a bridge next the shore; a pier which by its strength and stability resists the thrust of an arch. {Pier glass}, a mirror, of high and narrow shape, to be put up between windows. {Pier table}, a table made to stand between windows. [1913 Webster]